Foscam Digital Tech via eBay offers the Foscam Outdoor 802.11g Wireless IP Camera, model no. FI8904W, for $69.99 with free shipping. (CameraTec via Amazon has it for the same price.) That's tied with our May mention and the lowest total price we could find today by $8. It features infrared motion detection, 640x480 resolution, and a waterproof and weatherproof housing.
Of note, Foscam Digital Tech via eBay is also offering free telephone support, which doesn't appear to be included when you purchase the camera elsewhere.